Drug delivery devices such as infusion pumps typically require high standards of controllability in order to ensure that the drug delivery is reliable and accurate. WO 2007/129317 by some of the present inventors teaches the use of a displacement-generating battery to drive a miniature drug delivery device. However, this application does not teach the control elements of such a device required to ensure accuracy and reliability. Intercalation is a known process whereby intercalating species within a battery cell penetrate an electrode and arrange themselves therein. The intercalating species can include an ion, a proton, an alkali metal or an alkaline earth metal. The electrode may undergo expansion or contraction upon intercalation. For example, the intercalating species may be a Lithion ion, and the electrode whose volume is changed may contain tin (Sn) or silicon (Si). In these examples and others, the volume change of the electrode can cause the battery cell to serve as an actuator capable of applying motion to a physical object connected to the actuator. The major expansion that can be provided by using a Lithium-Tin intercalation reaction is known in the prior art. For example, the University of South Carolina Research has been reported a volume expansion of 259%. Prior art describing the use of intercalation to perform actuation includes U.S. Pat. No. 6,577,039, US 20060102455 as well as references cited by these patents.
WO 2007/010522 in the name of the present applicant teaches a drug delivery device that utilizes the volume expansion to implement a slow-infusion drug-delivery device.
WO 2007/129317 also in the name of the present applicant and published Nov. 15, 2007 (i.e. after the priority of the present application) likewise teaches a drug delivery device that utilizes the volume expansion to implement a slow-infusion drug-delivery device
US 2007/0062250 describes a servo-type control mechanism for an electronically controlled infusion pump where a (magnetic) position sensor is the source of positional feedback for the controller of the pump. The actual position, as determined solely by this sensor, is compared to the desired or expected position, and the pump powered accordingly in order to close any gap between the actual and the theoretical.